Compass Query

Back in the 1950s and 60s, I was an ‘Instrument Basher’ in the RAAF. During my technical training, I was taught, amongst other weird things, about the DRC (Direct Reading Compass) as fitted to Lancasters, Lincolns etc. The history of our great wartime aircraft is not complete without a mention of the internal bits, so read on!

The DRC was a wonderfully eccentric piece of machinery that looked like a small dustbin hung on articulated mounts in the rear fuselage. With its case off, you could watch the servo mechanism hunting to and fro and, if you touched it with a finger, the motorised frame whizzed around and almost took the tip off your finger! It was an entertainment just to watch it.

I only saw this instrument in a few RAAF Lincolns, because it was superseded by a GM2 gyro compass made by Smiths (not Sperry), but that’s another story. The ‘dustbin’ had a magnetic sensor inside which rotated according to the bearing. This was clamped every few seconds onto electrical contacts to motor the whole mechanism around to provide remote compass indications. It was not a gyro compass.

The point of this entry is that I saw a similar item in the Midlands Air Museum (MAM) recently, but this instrument appears to include a gyro. Anyone know if this was a development of the original, perhaps a DRGC? (think about it!). See Pic: apologies for the poor quality but the lighting, location and glass case made taking it difficult.

Bri